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Tire size question

11729 Views 8 Replies 6 Participants Last post by  CISA2016
I have been lurking here for a while, but still could not seem to find an answer for my question. I know for the rear tire that stock size is 140/75r15 and you can go up to 160/80r15 with no mods on stock wheels.

The front is where my question comes from. Stock size is 100/80r17. I know quite a few poeple run 110/80r17. One person ran a 120/90r17 but had to remove the front fender to get it to fit. He did not specify if the fender was the issue or if that wide of a tire was rubbing on the fender mounting bolts. If it was a tall clearance issue, wide clearance issue or both.

My question is: my front tire size that I would like to run is a 110/80r17 or a 120/70r17
Can the 120/70r17 fit with no mods? I don't want to remove the fender. The 110 would be slightly taller so I know it'll fit tall clearance wise. I just don't know if the 120 will fit wide clearance wise.
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I ran with that exact size combination (120-70/17 & 160-80/15) for a little over a year. See post for reference:

The combination did take some getting used to, turning in was quicker than stock and it did take a month or so to get used to. Other than that, no issues. I originally changed to eliminate exhaust scraping and it worked as intended. Note that I also changed from stock suspension to heavy duty progressives in the rear to prevent potential rubbing.
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Your post was one of the many I had read. The only thing that threw me off was the fact you were using the 12.5 progressive shocks. I knew that lowering the bike since stock is 13? Adjusted the amount closeness the tire was in the rear. But also noted that if the back goes down, usually the front will go up some from the offset. And I didn't know if that would cause enough of a difference between the two sizes.
In my case specifically, the front went up a negligible amount. I use tacomaworld for all of my tire size/ ratio determinations. With dropping the rear suspension .5", the 160/80-15 raised the rear back up by .76" (sidewall height difference from stock).

Overall the changes amounted to +.26" in the rear and +.16" up front. To me the difference seemed negligible, and since both front and rear tires widths increased, steering characteristics did not change by any large degree. By "turning in being quicker," I meant this as a result of being able to lean the bike further which again took some getting used to. That being said, I have since back to 13" shocks and a 19" front wheel on my 750 and I've had no issues.
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